Abstract: A hot melt foam adhesive system including a gear pump wherein gas is mixed under pressure into the molten adhesive and is driven into solution with the adhesive. The gas is supplied to the pump via a one-way check valve operative to prevent the back flow of molten adhesive to a gas flow control valve, regulator, and gauge. The check valve is positioned above the level of the pump so that molten adhesive cannot flow by gravity into the check valve. The check valve is so constructed that it is biased into a closed position by a spring on the gas side of the valve so that adhesive cannot collect around and foul the spring of the valve.

Abstract: A flexible heated hose for transporting molten adhesive from a melter to a dispenser. The hose comprises a Teflon tube contained within stainless steel braided wire and fitted with conventional hydraulic fittings at each end. The braided tube is encased within a multiple ply covering which includes a first layer of fiberglass tape around which are wound electrical resistance heating wires, a resistance temperature detector, electrical leads including a ground wire, and two plies of helically wound fiberglass tape, with a layer of helically wound Aramid fiber, two layers of helically wound polyester felt, and a layer of helically wound vinyl tape covering the same. The heating wires, electrical leads, and temperature detector are adhesively secured to the first layer of fiberglass tape which is in turn adhesively secured to the stainless steel braided wire covering the Teflon tube. In a modified embodiment, the ground wire is wound separate from the other electrical leads.

Abstract: A hot melt foam adhesive system including a gear pump wherein gas is mixed under pressure into the molten adhesive and is driven into solution with the adhesive. The adhesive/gas solution is supplied at a relatively high pressure to a valved dispenser or gun from where it is dispensed onto a substrate. As the adhesive/gas solution emerges from the dispenser, the gas comes out of solution but remains entrapped in the adhesive, thereby forming an adhesive foam. The system includes a recycle flow line or hose for returning adhesive/gas solution from the dispenser to the pump. Within this recycle flow line there is a pressure regulator responsive to flow changes or viscosity changes of the adhesive/gas solution for maintaining a fixed back pressure in the system, thereby enabling the system to maintain a fixed and uniform flow rate from the dispenser during all operating conditions of the dispenser.

Abstract: An apparatus for melting and dispensing thermoplastic material comprising a melter tank, a pump contained within the melter tank, a dispenser, and a manifold block mounted on the bottom of the melter tank. Thermoplastic material melted in the tank flows from the melter tank, through the pump, through the manifold block, to the dispenser. The pump is mounted in the tank and is either a reciprocating piston type or a rotary gear type pump, the two being interchangeable upon the tank. If a gear type pump is used, it is provided with a built-in pressure control valve operable to circulate the pump flow back to the tank when the dispenser flow is terminated or when there is greater pump flow than is required at the dispenser. Contained interiorly of the manifold block in the flow path between the pump and the dispenser there is a replaceable filter.

Abstract: A flexible electrically heated hose for transporting molten adhesive from a melter to a dispenser. The hose comprises a Teflon tube contained within stainless steel braided wire and fitted with conventional hydraulic fittings at each end. The braided tube is encased within a multiple ply covering which includes electrical resistance heating wires and a resistance temperature detector adhered between two plies of helically wound fiberglass tape. This tape is covered by multiple plies of helically wound, double thickness fiberglass paper between the plies of which there are embedded spiral wound electrical leads to the dispenser. The fiberglass paper layer is encased within two layers of helically wound polyester felt, a layer of helically wound vinyl tape, and a braided polyester cover. Hard molded plastic cuffs are attached to the ends of the hose. The electrical leads to the heating wires, temperature detector and dispenser extend radially from the hose through holes in the cuffs.

Abstract: A multi-position waveguide switch including a cylindrical housing supporting radially extending waveguides, a switching assembly composed of a stack of disks each having input and output ports interconnected by waveguide sections, and a mechanism for selectively translating the stack of disks to selected axial positions within the cylindrical housing such that a selected disk is in alignment and communication with certain predetermined ports of the radially extending waveguides. By selective axial translation of the disk assembly, a selected disk may be interposed between the radially extending waveguide supported by the housing to provide a selected routing path for microwave energy to the waveguides supported by the housing and through the selected disk.